Tank lorry for hygienic transport of milk

Abstract: A hygienic tank lorry pump for pumping liquid articles of food, such as milk, from a stationary tank (20) to the tank (2) of a tank lorry for pumping between the latter tank (2) and a trailer tank coupled to the tank lorry. The hygienic pump is formed by a side channel pump which can be driven by a hydraulic motor (17) in turn driven by a hydraulic system (6) of the tank lorry. As a result the tank lorry pump is self-priming, presents a high capacity relative to weight, as well as satisfying, simple cleaning possibilities.

Description: The invention relates to a hygienic tank lorry for transport of milk, said lorry having a pump for pumping the milk from a stationary tank on the ground to a tank on the lorry or between the latter tank and a trailer tank coupled to the tank lorry, the latter having a hydraulic system. Such a lorry is known from WO-A-8 503 572. Previously, a hygienic tank lorry pump of the self-priming type was used for pumping milk from the stationary milk tank of a farmer into the mobile tank lorry of the dairy. When the tank lorry is coupled to a trailer tank, viz. a trailer for a lorry, the pump in question is often used for pumping milk from the tank of the tank lorry into the trailer tank. At the dairy the tank of the tank lorry and the trailer tank are, however, emptied by means of another pump. Previously either a vacuum pump, viz. a rotor compressor or a rotor vacuum pump, or a conventional liquid ring pump was used as tank lorry pump due to the demand for an automatic drawing capacity, said pumps being provided with either eccentrically arranged rotor blades or with worm/screw in the liquid ring. The structure of vacuum pumps provides said pumps with a satisfying self-priming capacity, but the pumping capacity (m 3 /h) is very low with the result that the users face long operation periods and a reduced efficiency of the tank lorry. In addition, a vacuum pump must be disassembled when it is to be cleaned. Conventional liquid ring pumps are seldomly used because they must be very large, heavy, and energy-demanding in order to yield the necessary capacity. These pumps are not hygienic either as they cannot be satisfactorily cleaned. DE-A-14 73 052 relates to a milk pump device which is movable and which may be placed on a lorry. Besides pumping, the device may meter the milk. There is no reference to a side channel pump. GB-A-953 883 relates to a transportable pump assembly, the pump being a side channel pump. There is no reference to any tank lorry or the pumped liquid being milk. The object of the invention is to provide a tank lorry of the above type where the pump combines the ability to be self-priming, high capacity 1relative to the weight, simple cleaning possibilities and gentle pumping of raw milk. The hygienic tank lorry according to the invention is characterised in that the pump is a self-priming side channel pump, which is driven by a hydraulic motor on the lorry, said motor in turn being driven by the hydraulic system. In this manner a satisfying automatic drawing capacity combined with a high pumping capacity is obtained. Furthermore, the pump can be hygienically cleaned by the so-called CIP-method (clean in place) involving an external pumping, i.e. a flushing according to a specific system without necessitating a disassembling of the parts of the pump. In addition, it turned out that the side channel pump does not destroy the fat structure of the raw milk during pumping of the milk. In other words the pump has no homogenizing effect on the milk. The advantages of the new tank lorry and its pump are as follows: high pumping capacity (increased efficiency of the tank lorry), high self-priming capacity of the pump it is easy to clean the pump hygienically by CIP; it does not require a disassembling of the pump, high efficiency compared to a liquid ring pump, limited maintainance, and compact structure of the pump, i.e. small volume and low weight. According to the invention, the central shaft of the side channel pump may advantageously be mounted on a countershaft mounted in a bearing housing, said countershaft being connected to the drive shaft of the hydraulic motor. Furthermore according to the invention the side channel pump may be provided with a drain cock for securing against frost and removal of residues of CIP-liquid (CIP = clean in place). In addition according to the invention the side channel pump may be mounted on the lorry adjacent the inlet of the tank thereof and in such a manner that a reliable priming of the side channel pump is allowed when said pump is to be started either by way of a natural inlet of milk from one of the tanks or by way of a manual priming or a self-priming. In this manner the side channel pump operates most efficiently. The side channel pump may according to the invention be mounted in an optionally height-adjustable hygienic box, and the bearing housing of the pump may optionally be mounted in a wall in the box, and the hydraulic motor may be mounted on the outside of the box, whereby the side channel pump is well protected. The invention is described in greater detail below with reference to the accompanying drawing, in which Figure 1 ilustrates a tank lorry provided with a side channel pump; a stationary tank is shown stading on the ground; and Figure 2 is a diagrammatic view of how the side channel pump is driven by a hydraulic motor of a hydraulic system associated with the tank lorry. The tank lorry 1 (truck) shown in Figure 1 is provided with a tank 2 for the transport of milk. The tank is filled or emptied by means of a tank lorry pump 30 not shown in Figure 1 but in Figure 2, said pump being mounted in a hygienic box 3 accommodated on a suitable level on the tank lorry. The tank lorry pump 30 is driven by a hydraulic motor not shown in the drawing, said hydraulic motor in turn being driven by the hydraulic system of the tank lorry indicated by the two broken lines 6. Figure 2 illustrates on a larger scale the used tank lorry pump which is a side channel pump 30. It comprises an inlet 7 and an impeller 8 with a considerable number of blades. The impeller is mounted at the end of a central shaft 9 in turn mounted in the housing 10 of the side channel pump. When the side channel pump is operating, i.e. when the impeller 8 rotates, the milk is pressed outwards inside the housing 10, and for instance from the "upper" part 8' said milk is pressed to the side and outwards into the side channel 11 of the pump and subsequently further out into the discharge pipe stub 12. As it appears the central shaft 9 of the side channel pump can be connected to a countershaft 13 in a bearing housing 14, and this countershaft 13 is in turn connected to a drive shaft 15 on the hydraulic motor 17. Adjacent the lowest end the side channel pump can be provided with a drain cock not shown for the removal of residues of cleaning fluid, viz. the fluid used for flushing and cleaning the pump, so-called CIP-fluid, cf. Figure 2. The cock can also be used for removing possible small residues of liquid in the pump, whereby it is avoided that these residues freeze and cause problems of frost bursts. The side channel pump 30 is mounted on the tank lorry adjacent the inlet 4 of the tank 2, and on such a level relative to a stationary tank 20 (or trailer tank, i.e. a tank not shown which is positioned on a trailer for the tank lorry 1) that it is ensured that the side channel pump 30 can be reliably primed when it is to be started. The priming is performed either by a natural flow of milk from the stationary tank or manually or automatically. The manual priming or the self-priming may involve a priming of the pump with a small amount of clean water. A suitable level for the box 3 and consequently for the side channel pump is the one shown in Figure 1 in connection with the position illustrated for the stationary tank 20. The connection between the inlet pipe stub 7 of the side channel pump and the outlet pipe stub 21 of the stationary tank 20 is a rubber or plastic hose not shown. The inlet pipe stub 4 of the tank is connected to the outlet pipe stub 12 of the side channel pump. Nothing, however, prevents various hoses and connections from being accommodated in other ways, such as when milk is to be pumped from the tank 2 into a trailer tank. In this case the pipe stub of the trailer tank is connected through a pipe hose to the outlet pipe stub 12 of the side channel pump, whereas the pipe stub 4 of the tank 2 is connected to the inlet pipe stub 7 of the pump. The above stationary tank 20 is a milk tank placed at each farmer. The content of the tank 20 is pumped by means of the side channel pump of the tank lorry into the tank 2. When the tank lorry reaches the dairy, the tank 2 is, however, usually emptied by means of a particular pumping equipment accommodated at the dairy, a stationary tank not shown at the dairy simultaneously being filled. This pumping equipment is not shown and has no relation to the present invention. Nothing, however, prevents the side channel pump from being used in this situation too. The hygienic box 3, cf. Figure 1, can be adjustable with respect to height because it can for instance be fixed in various positions in the height on a ladder-like arrangement not shown which is secured to the chassis of the tank lorry. As mentioned above, the side channel pump and the bearing housing 14 as well as the hydraulic motor 17 can be mounted inside the box 3. The side channel pump can, however, also be mounted such that the pump itself is positioned inside the box while the bearing housing 14 is mounted in the wall of the box and the hydraulic motor 17 is mounted on the outside of said box. In Figure 2, 18 and 19 indicate the pipe stubs, viz. the inlet pipe stub and the outlet pipe stub, connected to the hydraulic system 6 of the tank lorry. The supply of hydraulic liquid for the hydraulic motor 17 is performed through pipes 6 in the hydraulic system of the tank lorry. These pipes are flexible over the length abutting the hydraulic motor 17 in such a manner that they can follow this motor when and if the level thereof on the tank lorry is changed.

Claims: A hygienic tank lorry (1) for transport of milk, said lorry having a pump for pumping the milk from a stationary tank (20) on the ground to a tank (2) on the lorry (1) or between the latter tank (12) and a trailer tank coupled to the tank lorry (1), the latter having a hydraulic system (6), characterised in that the pump is a self-priming side channel pump (30), which is driven by a hydraulic motor (17) on the lorry, said motor in turn being driven by the hydraulic system (6). A lorry as claimed in claim 1, characterised in that the central shaft (9) of the side channel pump (30) is mounted on a countershaft (13) mounted in a bearing housing (14), said countershaft being connected to the drive shaft (15) on the hydraulic motor (17). A lorry as claimed in claim 1 or 2, characterised in that the side channel pump (30) is provided with a drain cock (at 16) for securing against frost and removal of residues of CIP-liquid (CIP = clean in place). A lorry as claimed in claim 1, 2 or 3, characterised in that the side channel pump (30) is mounted on the lorry (1) adjacent the inlet (4) of the tank (2) in such a manner that a reliable priming of the pump (30) is allowed when said pump is to be started either by way of a natural inlet of milk from one of the tanks or by way of a manual priming or a self-priming. A lorry as claimed in claim 4, characterised in that the side channel pump (30) is mounted in an optionally height-adjustable hygienic box (3), and that the bearing housing (14) is optionally mounted in a wall in the box (3), the hydraulic motor (17) being mounted on the outside of the box (3).

Inventors: AGGER FRODE, AGGER, FRODE
Applicants: APV ROSISTA AS, APV ROSISTA A/S
Application year: 1994
Main classification: F04D5
IPC codes: F04D13, F04D5, G01G17, B60P3